The acquired enamel pellicle (EP) plays a pivotal role in the caries process. The pruporse of this proposal is to elucidate the mechanisms that control activity at the tooth/saliva interface. A model system, consisting of mucin-glycopriten and synthetic hydroxyapatite will be used in these studies. We will explore the structural determinants that are responsible for the selective deposition of mucin-glycoprotein to hydroxyapatite. In addition the susceptibility of mucin-glycoprotein to conformational change and structural modification during and after adsorption to hydroxyapatite will be assessed.